1. Field of the Invention
The present invention relates to an air-conditioning blow-out port unit to be mounted in an instrument panel or the like in an automobile, and particularly, to an improvement in air-conditioning blow-out port unit comprising a housing formed by a primary injection molding of synthetic resin and having a plurality of coaxially arranged pairs of shaft holes provided in opposed sidewalls, and a plurality of blades formed in the housing by a secondary injection molding of synthetic resin and each having a blade body and a pair of support shafts projectingly provided at opposite sides of the blade body and turnably fitted in each pair of the shaft holes.
2. Description of the Prior Art
An air-conditioning blow-out port unit of such type is already known, as disclosed, for example, in Japanese Patent Publication No. 48745/84.
In the prior art air-conditioning blow-out port unit, when the blades are formed by the secondary injection molding, an expanded head portion is formed at a tip and of each support shaft to abut against an outer surface of the housing. This expanded head portion is brought into a press contact with the outer surface of the housing by a thermal shrinkage occurring after the formation of the blades and functions to retain the blades in their turned positions by a friction resistance produced therebetween.
However, the blade is relatively long in a direction of the support shaft and for this reason, the following problem is encountered in use: The blade may be expanded and shrunk in a relatively large amount in the direction of the support shaft due to the variation in temperature of the surroundings, which is attended by a large increase and decrease in friction resistance between the expanded head portion and the housing, resulting in a variation in feeling of turning of the blade.